I dont like locking down the half guard. I take the outside leg and hook it over the opponents leg because as he said its eaier to get the hips out and replace the guard. If i do hook the halfguard i will keep the inside leg hooked around the back of the opponents leg so i can take my outside leg out and put it on inside of the leg on the same side. This gives me a butter fly hook i can use to sweep or another method to replace the guard if im having trouble hipping out.